A. Field of the Invention
The present invention relates to a method of plant husbandry and product produced thereby, as in a composition and article of manufacture. More particularly, the present invention pertains to structures for aiding in manufacturing, transporting, and installing reinforced growing media with plant roots and crowns therein. Even more particularly, the present invention relates to improvements to wildflower sod fabrics, arrays, and layouts.
B. Background of the Invention
Growing, harvesting, transporting, and planting rolls of sod per se is well known. Installation includes using large staples or stakes to secure the sod to the ground, particularly for a slope or swale.
For growing plants other than grasses, such as wildflowers, young root masses are generally not considered strong enough to harvest, transport, and install in the manner of grass sod. Thus, certain kinds of mats and rolls have been used in the seed and plant industry as a convenient device for the transport, storage, and installation of seeds and such seedlings. These kinds of products generally are prepared using a base sheet (of, say, polyester fabric), upon which the propagating medium and seeds are deposited. See, for example, U.S. Pat. No. 4,941,282, titled Wildflower Sod Mat and Method of Propagation.” Sometimes a protective upper sheet or veil is positioned over the medium, and occasionally, some form of adhesive is used to bind each layer to the next, i.e., the protective covering to the propagating medium, and the propagating medium to the base sheet. The product of such an approach is something resembling a laminate.
There are a number of drawbacks to such an approach. The laminates are expensive to produce and thus are costly to the consumer; but most importantly, the laminates of the known prior art prevent root crowns from full contact with the earth below the laminates, which in turn directly effects the survivability of the seedlings.
Additionally, the staples and stakes used to secure sod to a slope or a swale do not work because the base sheet interferes with the bonding of the roots to the earth.
Alternatively, humus or mulch has been used as the propagating medium. Humus or mulch expands upon exposure to moisture, thereby breaking down the base sheet material before final installation and planting of the roll or mat. Such expansion, however, also has an additional disadvantage: the seeds and the propagating medium can be washed away from the base sheet material due to the expansion. Stitching to form layers of the protective covering, seeds, medium, and base also proved to have its disadvantages. Stitching tends to inhibit the expansion of the propagating medium, forming an irregular bottom surface and only partial contact with the earth, which again decreases the survival rate of the seedlings.
Base sheets have also been problematic. Some base sheets are completely biodegradable upon wetting, and as a result, the laminates fall apart during attempts at transporting, storing, and installing. Other base sheets are impervious to moisture, such that seed germination is inhibited by poor drainage.
Furthermore, alternative types of base sheets are impervious to root penetration, which prevents meshing of the base sheet with the seedling root mass. Therefore, the base sheet acts as a carrier for the sod, rather than as an integral part thereof.
The advent of a pervious base sheet (e.g., of polyester fabric) has partially solved the problem of integrating the root mass of the seedlings with the base sheet to form a stronger sod mat. A disadvantage of having a pervious barrier formed by the base sheet, however, is that the root crown's of the seedlings are on one side of the barrier and only the roots penetrating the fabric are on the other side so as to ultimately come into contact with the earth. This condition adversely effects the long term survivability of the seedlings sod matrix, by the loss of winter hardiness from exposing the root crowns to the elements—with a general decline in seedling vigor, which eventually results in plant death.
Another disadvantage is that the base sheets (and other such structures) are not biodegradable, so that a subsequent planting requires removal of the base sheet or other such structure.
The laminates have been formed in a container, such as a plastic tray, to produce mats with a homogeneous mixture of seeds (wildflowers). See again, U.S. Pat. No. 4,941,282, titled Wildflower Sod Mat and Method of Propagation.” But the use of trays is not helpful for large commercial applications.
For such commercial applications, where transporting the seeds and media are not an issue, seeds have been held in place by applying a web, net, or blanket over the seeds. This approach is encountered in erosion control.